How do you graph #5y<=-x-20#?

1 Answer
Sep 19, 2015

Graph and solve #5y <= - x - 20#

Explanation:

Put the inequality in standard form:
#5y + x + 20 <= 0# (1).
First, graph the Line --> 5y + x + 20 = 0 by its 2 intercepts.
Make x = 0 --> y = -4. Make y = 0 --> x = -20.
Next, solve the inequality (1). The solution set is the area below the Line. Color it. Since there is the sign (=), the Line is included in the solution set.
graph{5y + x + 20 = 0 [-20, 20, -10, 10]}

Note. You can check the answer by using the origin O as test point. Substitute x = 0 and y = 0 into (1), we get #20 <= 0.# It is untrue. Then the solution set area doesn't contain O.